onsemi 74LVTH240MTCX

Overview

74LVTH240MTCX from Fairchild Semiconductor is an inverting octal buffer/line driver with 3-STATE outputs, designed for 3.3V V_CC operation while interfacing to 5V TTL systems. It features bushold inputs (eliminating external pull-ups), ±32mA/64mA drive capability, and operates across –40°C to +85°C - used in memory address driving and clock distribution on dense PCBs.

For engineers reviewing the 74LVTH240MTCX datasheet, pinout, applications, or equivalent options, key selection criteria include bushold input support, 3.3V/5V mixed-voltage bus compatibility, high-current 3-STATE output drive, thermal reliability in industrial environments, and TSSOP-20 package footprint constraints.

Technical Context

The 74LVTH240MTCX implements dual 4-bit inverting buffers with independent 3-STATE control (OE1/OE2), enabling flexible bus partitioning. Its bushold circuitry actively maintains input logic state without external biasing - confirmed for all eight data inputs (I0–I7) per datasheet Section 2.

It uses advanced BiCMOS fabrication to achieve propagation delays as low as 1.1ns (t_PLH/t_PHL) at 3.3V while limiting ICCZ to 0.19mA in disabled state. Output skew is specified ≤1.0ns between any two outputs switching in the same direction, supporting synchronized multi-line signaling.

Key Specifications

Pinout & Package

74LVTH240MTCX is housed in a 20-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm wide, with 0.65mm lead pitch and exposed pad not present. Pin spacing and thermal profile comply with IPC-7351B land pattern recommendation MTC20.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal buffer applications.

Compared with 74LVTH240MTCX, SN74LVC240APWR lacks bushold and 5V input tolerance - limiting use in mixed-voltage buses - while 74ALVT240MTCX trades higher static current for faster edges, making it preferable only where propagation delay dominates power budget.

Availability

74LVTH240MTCX is available at Aetrix Electronics and suitable for memory address buffering, industrial I/O expansion, and clock distribution requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant TSSOP packaging.

Supply support for 74LVTH240MTCX includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and mixed-signal ICs, acquired by ON Semiconductor in 2016. Its legacy logic portfolio remains widely deployed in industrial and computing infrastructure.

The 74LVTH240MTCX belongs to Fairchild's LVT/H series of low-voltage BiCMOS buffers - engineered for high-speed, low-power 3.3V-to-5V interface bridging in memory, bus, and clock subsystems.

FAQ

What is the bushold functionality of the 74LVTH240MTCX and how does it affect circuit design?

The 74LVTH240MTCX incorporates bushold circuitry on all eight data inputs (I0–I7), which actively retains the last valid logic state without external pull-up or pull-down resistors. This eliminates BOM items and layout area typically needed for unused inputs, reducing risk of floating nodes during power-up or standby. The bushold current is ±75µA at 0.8V/2.0V, ensuring reliable state hold across temperature and voltage variations - a feature absent in the non-H variant 74LVT240MTCX.

Can the 74LVTH240MTCX safely interface between a 3.3V microcontroller and 5V peripherals?

Yes, the 74LVTH240MTCX supports true 5V-tolerant inputs (VI up to 5.5V) and can drive 5V TTL loads with its ±32mA/64mA output capability. Its V_CC is strictly 2.7–3.6V, so the device itself runs at 3.3V while accepting 5V logic levels on inputs and delivering compatible output voltages (VOH ≥ V_CC–0.2V, VOL ≤ 0.55V at 64mA). No level-shifting circuitry is required, simplifying inter-voltage domain signal routing.

What is the significance of the dual output-enable pins (OE1 and OE2) on the 74LVTH240MTCX?

The 74LVTH240MTCX splits its eight outputs into two groups of four (O0–O3 controlled by OE1; O4–O7 by OE2), allowing independent 3-STATE control of each half. This enables partial bus isolation - for example, holding one memory bank active while tri-stating another - improving system flexibility and reducing contention during multi-master arbitration. Both enables are active-low and share identical electrical specs (t_PZH/t_PZL ≤ 5.6ns), supporting synchronized or staggered enable timing.

How does the 74LVTH240MTCX handle power sequencing during system startup and shutdown?

The 74LVTH240MTCX features power-up/power-down high-impedance behavior: outputs remain in 3-STATE regardless of OE1/OE2 state until V_CC reaches ~1.5V, and re-enter high-Z when V_CC drops below that threshold. This prevents bus contention and glitch generation during supply ramping - critical in systems with asymmetric power sequencing. Measured I_PU/PD is ±100µA, confirming minimal disturbance to upstream regulators during transition.

Is the 74LVTH240MTCX suitable for industrial environments with extended temperature ranges?

Yes, the 74LVTH240MTCX is rated for operation from –40°C to +85°C and tested per JEDEC standards for latch-up (>500mA) and ESD (HBM > 2000V). Its BiCMOS process ensures stable propagation delay (1.1–4.6ns) and output drive across this range, and the TSSOP-20 package (MTC20) has proven reliability in vibration-prone and thermally cycled industrial enclosures - consistent with Fairchild's qualification for embedded control and automation applications.